kernel/power/suspend.c

   1 /*
   2  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   7  *
   8  * This file is released under the GPLv2.
   9  */
  10
  11 #include <linux/string.h>
  12 #include <linux/delay.h>
  13 #include <linux/errno.h>
  14 #include <linux/init.h>
  15 #include <linux/console.h>
  16 #include <linux/cpu.h>
  17 #include <linux/cpuidle.h>
  18 #include <linux/syscalls.h>
  19 #include <linux/gfp.h>
  20 #include <linux/io.h>
  21 #include <linux/kernel.h>
  22 #include <linux/list.h>
  23 #include <linux/mm.h>
  24 #include <linux/slab.h>
  25 #include <linux/export.h>
  26 #include <linux/suspend.h>
  27 #include <linux/syscore_ops.h>
  28 #include <linux/ftrace.h>
  29 #include <trace/events/power.h>
  30 #include <linux/compiler.h>
  31
  32 #include "power.h"
  33
  34 struct pm_sleep_state pm_states[PM_SUSPEND_MAX] = {
  35         [PM_SUSPEND_FREEZE] = { "freeze", PM_SUSPEND_FREEZE },
  36         [PM_SUSPEND_STANDBY] = { "standby", PM_SUSPEND_STANDBY },
  37         [PM_SUSPEND_MEM] = { "mem", PM_SUSPEND_MEM },
  38 };
  39
  40 static const struct platform_suspend_ops *suspend_ops;
  41
  42 static bool need_suspend_ops(suspend_state_t state)
  43 {
  44         return state > PM_SUSPEND_FREEZE;
  45 }
  46
  47 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  48 static bool suspend_freeze_wake;
  49
  50 static void freeze_begin(void)
  51 {
  52         suspend_freeze_wake = false;
  53 }
  54
  55 static void freeze_enter(void)
  56 {
  57         cpuidle_use_deepest_state(true);
  58         cpuidle_resume();
  59         wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
  60         cpuidle_pause();
  61         cpuidle_use_deepest_state(false);
  62 }
  63
  64 void freeze_wake(void)
  65 {
  66         suspend_freeze_wake = true;
  67         wake_up(&suspend_freeze_wait_head);
  68 }
  69 EXPORT_SYMBOL_GPL(freeze_wake);
  70
  71 /**
  72  * suspend_set_ops - Set the global suspend method table.
  73  * @ops: Suspend operations to use.
  74  */
  75 void suspend_set_ops(const struct platform_suspend_ops *ops)
  76 {
  77         lock_system_sleep();
  78         suspend_ops = ops;
  79         unlock_system_sleep();
  80 }
  81 EXPORT_SYMBOL_GPL(suspend_set_ops);
  82
  83 bool valid_state(suspend_state_t state)
  84 {
  85         if (state == PM_SUSPEND_FREEZE) {
  86 #ifdef CONFIG_PM_DEBUG
  87                 if (pm_test_level != TEST_NONE &&
  88                     pm_test_level != TEST_FREEZER &&
  89                     pm_test_level != TEST_DEVICES &&
  90                     pm_test_level != TEST_PLATFORM) {
  91                         printk(KERN_WARNING "Unsupported pm_test mode for "
  92                                         "freeze state, please choose "
  93                                         "none/freezer/devices/platform.\n");
  94                         return false;
  95                 }
  96 #endif
  97                         return true;
  98         }
  99         /*
 100          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEMORY states need lowlevel
 101          * support and need to be valid to the lowlevel
 102          * implementation, no valid callback implies that none are valid.
 103          */
 104         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 105 }
 106
 107 /**
 108  * suspend_valid_only_mem - Generic memory-only valid callback.
 109  *
 110  * Platform drivers that implement mem suspend only and only need to check for
 111  * that in their .valid() callback can use this instead of rolling their own
 112  * .valid() callback.
 113  */
 114 int suspend_valid_only_mem(suspend_state_t state)
 115 {
 116         return state == PM_SUSPEND_MEM;
 117 }
 118 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 119
 120 static int suspend_test(int level)
 121 {
 122 #ifdef CONFIG_PM_DEBUG
 123         if (pm_test_level == level) {
 124                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 125                 mdelay(5000);
 126                 return 1;
 127         }
 128 #endif /* !CONFIG_PM_DEBUG */
 129         return 0;
 130 }
 131
 132 /**
 133  * suspend_prepare - Prepare for entering system sleep state.
 134  *
 135  * Common code run for every system sleep state that can be entered (except for
 136  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 137  * freeze processes.
 138  */
 139 static int suspend_prepare(suspend_state_t state)
 140 {
 141         int error;
 142
 143         if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter))
 144                 return -EPERM;
 145
 146         pm_prepare_console();
 147
 148         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 149         if (error)
 150                 goto Finish;
 151
 152         error = suspend_freeze_processes();
 153         if (!error)
 154                 return 0;
 155
 156         suspend_stats.failed_freeze++;
 157         dpm_save_failed_step(SUSPEND_FREEZE);
 158  Finish:
 159         pm_notifier_call_chain(PM_POST_SUSPEND);
 160         pm_restore_console();
 161         return error;
 162 }
 163
 164 /* default implementation */
 165 void __weak arch_suspend_disable_irqs(void)
 166 {
 167         local_irq_disable();
 168 }
 169
 170 /* default implementation */
 171 void __weak arch_suspend_enable_irqs(void)
 172 {
 173         local_irq_enable();
 174 }
 175
 176 /**
 177  * suspend_enter - Make the system enter the given sleep state.
 178  * @state: System sleep state to enter.
 179  * @wakeup: Returns information that the sleep state should not be re-entered.
 180  *
 181  * This function should be called after devices have been suspended.
 182  */
 183 static int suspend_enter(suspend_state_t state, bool *wakeup)
 184 {
 185         int error;
 186
 187         if (need_suspend_ops(state) && suspend_ops->prepare) {
 188                 error = suspend_ops->prepare();
 189                 if (error)
 190                         goto Platform_finish;
 191         }
 192
 193         error = dpm_suspend_end(PMSG_SUSPEND);
 194         if (error) {
 195                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 196                 goto Platform_finish;
 197         }
 198
 199         if (need_suspend_ops(state) && suspend_ops->prepare_late) {
 200                 error = suspend_ops->prepare_late();
 201                 if (error)
 202                         goto Platform_wake;
 203         }
 204
 205         if (suspend_test(TEST_PLATFORM))
 206                 goto Platform_wake;
 207
 208         /*
 209          * PM_SUSPEND_FREEZE equals
 210          * frozen processes + suspended devices + idle processors.
 211          * Thus we should invoke freeze_enter() soon after
 212          * all the devices are suspended.
 213          */
 214         if (state == PM_SUSPEND_FREEZE) {
 215                 freeze_enter();
 216                 goto Platform_wake;
 217         }
 218
 219         ftrace_stop();
 220         error = disable_nonboot_cpus();
 221         if (error || suspend_test(TEST_CPUS))
 222                 goto Enable_cpus;
 223
 224         arch_suspend_disable_irqs();
 225         BUG_ON(!irqs_disabled());
 226
 227         error = syscore_suspend();
 228         if (!error) {
 229                 *wakeup = pm_wakeup_pending();
 230                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 231                         error = suspend_ops->enter(state);
 232                         events_check_enabled = false;
 233                 }
 234                 syscore_resume();
 235         }
 236
 237         arch_suspend_enable_irqs();
 238         BUG_ON(irqs_disabled());
 239
 240  Enable_cpus:
 241         enable_nonboot_cpus();
 242         ftrace_start();
 243
 244  Platform_wake:
 245         if (need_suspend_ops(state) && suspend_ops->wake)
 246                 suspend_ops->wake();
 247
 248         dpm_resume_start(PMSG_RESUME);
 249
 250  Platform_finish:
 251         if (need_suspend_ops(state) && suspend_ops->finish)
 252                 suspend_ops->finish();
 253
 254         return error;
 255 }
 256
 257 /**
 258  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 259  * @state: System sleep state to enter.
 260  */
 261 int suspend_devices_and_enter(suspend_state_t state)
 262 {
 263         int error;
 264         bool wakeup = false;
 265
 266         if (need_suspend_ops(state) && !suspend_ops)
 267                 return -ENOSYS;
 268
 269         trace_machine_suspend(state);
 270         if (need_suspend_ops(state) && suspend_ops->begin) {
 271                 error = suspend_ops->begin(state);
 272                 if (error)
 273                         goto Close;
 274         }
 275         suspend_console();
 276         suspend_test_start();
 277         error = dpm_suspend_start(PMSG_SUSPEND);
 278         if (error) {
 279                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 280                 goto Recover_platform;
 281         }
 282         suspend_test_finish("suspend devices");
 283         if (suspend_test(TEST_DEVICES))
 284                 goto Recover_platform;
 285
 286         do {
 287                 error = suspend_enter(state, &wakeup);
 288         } while (!error && !wakeup && need_suspend_ops(state)
 289                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 290
 291  Resume_devices:
 292         suspend_test_start();
 293         dpm_resume_end(PMSG_RESUME);
 294         suspend_test_finish("resume devices");
 295         resume_console();
 296  Close:
 297         if (need_suspend_ops(state) && suspend_ops->end)
 298                 suspend_ops->end();
 299         trace_machine_suspend(PWR_EVENT_EXIT);
 300         return error;
 301
 302  Recover_platform:
 303         if (need_suspend_ops(state) && suspend_ops->recover)
 304                 suspend_ops->recover();
 305         goto Resume_devices;
 306 }
 307
 308 /**
 309  * suspend_finish - Clean up before finishing the suspend sequence.
 310  *
 311  * Call platform code to clean up, restart processes, and free the console that
 312  * we've allocated. This routine is not called for hibernation.
 313  */
 314 static void suspend_finish(void)
 315 {
 316         suspend_thaw_processes();
 317         pm_notifier_call_chain(PM_POST_SUSPEND);
 318         pm_restore_console();
 319 }
 320
 321 /**
 322  * enter_state - Do common work needed to enter system sleep state.
 323  * @state: System sleep state to enter.
 324  *
 325  * Make sure that no one else is trying to put the system into a sleep state.
 326  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 327  * system enter the given sleep state and clean up after wakeup.
 328  */
 329 static int enter_state(suspend_state_t state)
 330 {
 331         int error;
 332
 333         if (!valid_state(state))
 334                 return -ENODEV;
 335
 336         if (!mutex_trylock(&pm_mutex))
 337                 return -EBUSY;
 338
 339         if (state == PM_SUSPEND_FREEZE)
 340                 freeze_begin();
 341
 342         printk(KERN_INFO "PM: Syncing filesystems ... ");
 343         sys_sync();
 344         printk("done.\n");
 345
 346         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state].label);
 347         error = suspend_prepare(state);
 348         if (error)
 349                 goto Unlock;
 350
 351         if (suspend_test(TEST_FREEZER))
 352                 goto Finish;
 353
 354         pr_debug("PM: Entering %s sleep\n", pm_states[state].label);
 355         pm_restrict_gfp_mask();
 356         error = suspend_devices_and_enter(state);
 357         pm_restore_gfp_mask();
 358
 359  Finish:
 360         pr_debug("PM: Finishing wakeup.\n");
 361         suspend_finish();
 362  Unlock:
 363         mutex_unlock(&pm_mutex);
 364         return error;
 365 }
 366
 367 /**
 368  * pm_suspend - Externally visible function for suspending the system.
 369  * @state: System sleep state to enter.
 370  *
 371  * Check if the value of @state represents one of the supported states,
 372  * execute enter_state() and update system suspend statistics.
 373  */
 374 int pm_suspend(suspend_state_t state)
 375 {
 376         int error;
 377
 378         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 379                 return -EINVAL;
 380
 381         error = enter_state(state);
 382         if (error) {
 383                 suspend_stats.fail++;
 384                 dpm_save_failed_errno(error);
 385         } else {
 386                 suspend_stats.success++;
 387         }
 388         return error;
 389 }
 390 EXPORT_SYMBOL(pm_suspend);